Michael R. Cohen, R.Ph.

President, Institute for Safe Medication Practices

Our sister organization, ISMP Canada, has received a number of medication error reports related to mix-ups between the brand names Plavix (clopidogrel) and Pradax (dabigatran). Plavix is also available in the US. Pradax is available here too, but it’s called Pradaxa in the US even though it is the same drug. I thought it would be useful to alert people taking Pradaxa to the possibility of a mix-up since there’s only the letter “a” at the end of the Canadian product that’s different.

Plavix is available in 75 mg and 300 mg tablets and the usual dose is 75 mg daily. Pradaxa is available in the US also as 75 mg and 150 mg capsules. A typical dose is 75 mg or 150 mg twice daily, depending on renal function. Since both have a 75 mg dosage form, prescriptions can more easily be misread, especially when prescriptions are handwritten and may not be clearly interpreted by the pharmacist. The names can even sound similar when prescriptions are called into the pharmacy by the doctor’s office.

Plavix stops blood platelets from sticking together and forming a clot. This makes it useful for lowering the risk of heart disease and stroke caused by blood clots. Aspirin also works similarly but Plavix is one of the newer antiplatelet drugs that doctors often use for this purpose. Pradaxa was marketed last year and is an anticoagulant used as a “blood thinner.” It inhibits a substance in the blood called thrombin, which is needed to make blood clot normally. Doctors are using it more and more as a replacement for Coumadin (warfarin) since it does not require frequent blood tests but seems to work just as well, although patients and doctors have to be cautious with it since it can cause excessive bleeding similar to Coumadin.

A mix-up between Plavix and Pradaxa could have serious consequences. If a patient is supposed to receive Plavix but receives Pradaxa in error, the patient will not experience the desired antiplatelet effect and could be at increased risk of bleeding. Similarly, if a patient is supposed to receive Pradaxa but Plavix is supplied, the patient will not experience the desired anticoagulant effect.

In one incident in Canada, a patient needed a procedure to treat a brain aneurysm. The patient was supposed to take Plavix with aspirin for several days before the procedure but there was a mix-up at the community pharmacy where the patient had the prescription filled, and the patient was given Pradax instead of Plavix. The patient took the Pradax capsules, along with the aspirin for several days before going to the hospital for the procedure. Fortunately, the patient remembered how important it is to bring a list of all of his medicines with him whenever he interfaced with a doctor or hospital for treatment. A pharmacist reviewed the medicines when the patient was admitted to the hospital, noticed the problem, and called the patient’s community pharmacy. The pharmacist there confirmed that the order for Plavix had been misinterpreted and that Pradax had been dispensed in error. The neurosurgeon was notified, and the procedure was postponed.

In previous blogs I’ve done about drug name mix-ups I’ve mentioned the importance of making sure the drug’s purpose is known to you and also that your pharmacist knows the reason you are taking a medicine. Both are important safety measures that usually can help to differentiate one look-alike drug name from another. But since these drugs both work to prevent dangerous blood clots, I’m not sure that will be all that helpful here. If you are taking either Plavix or Pradaxa keep the possibility of this particular name mix-up. Then, after you have the prescription filled, be sure to open the bag before you leave the pharmacy. Read the name of the drug on the container label and the accompanying drug information sheet to make sure you have the right drug. Also, ask the pharmacist to go over the name of the drug and the detailed instructions with you. If any of the information that your pharmacist provides does not match what you were expecting to see or hear, tell the pharmacist immediately.